Achiral or chiral phosphines are widely used in two main domains: ligands in organometallic catalysis and organocatalysis. For this reason, the obtention of optically pure phosphine has always been challenging in the development of asymmetric catalysis. The simplest method to obtain phosphines is the reduction of phosphine oxides. The essential difficulty is the strength of the P=O bond which involves new procedures to maintain a high chemio- and stereoselectivity. The reduction can occur with retention or inversion of the stereogenic phosphorus atom depending on the nature of the reducing agent and the presence of additives. In fact, the reactivity of the phosphine oxides and the mechanism of the reduction are not always well understood. Since the first work in the 1950's, numerous studies have been realised in order to develop methodologies with different reagents or to understand the mechanism of the reaction. In the last decade, efficient stereospecific methodologies have been developed to obtain optically pure tertiary phosphines from P-stereogenic phosphine oxides. In this review, we intend to provide a comprehensive and critical overview of these methodologies.

A new family of H-adamantylphosphinates as universal precursors of P-stereogenic ligands was obtained in one step from commercial chlorophosphines. Both enantiomers of these air- and moisture-stable intermediates can easily be separated by semipreparative chiral HPLC on a gram scale and individually undergo stereoselective transformations to afford each enantiomer of a set of P-stereogenic compounds such as secondary phosphine oxides and boron-protected monophosphines.